The Huskies (48-12) won the best of three super-regional against the Utes (37-16) and advanced to Oklahoma City for the 12th time in program history and first time since 2013.
The win also guarantees that seniors Aguilar and Casey Stangel will finish their careers as Huskies with at least one trip to the WCWS.
Trailing 2-1 in the top of the seventh, the Utes, much like the Huskies did in game 2 had the best case scenario for staying slide with the top of the order coming up to bat, especially Flippen, who came into the game leading Utah with a .423 average and 10 home runs and ranked second on the team in runs batted in with 50.
Alvelo (32-7), however, had surprisingly little trouble dispensing of the Utes in order. She retired Breonna Castaneda on one pitch on a fly ball to right fielder Trysten Melhart. Alyssa Barrera then popped out on one pitch to shortstop Aguilar for the second out.
Flippen came up representing the tying run, and took one ball before looping a ball toward the line in shallow left that Aguilar had time to glove and the celebration was on. Aguilar threw the ball up in the air and the Huskies mobbed around the pitching circle.
After Utah and Washington combined for 17 runs in a 9-8 Utah win in Game 2, Game 3 surprisingly turned into a pitcher's duel between Alvelo and Katie Donovan (18-10), who responded nicely after getting hammered the previous game.
Both threw complete games. Alvelo went seven innings, allowing one run on eight hits while walking two - one intentionally - and striking out three. Donovan went six innings, allowing two runs on only three hits while walking three and striking out two.
Washington took a 1-0 lead in the home half of the first when Aguilar led off with a line single to right, advanced to second on a walk, took third on a fielder's choice, and scored on a wild pitch.
The Huskies went up 2-0 in the second when Melhart drew a leadoff walk, took second on a line single to center by Kirstyn Thomas, moved to third on a sacrifice by Kelly Burdick, and scored on a sacrifice fly to right by Aguilar. One pitch before she flied out to right Aguilar hit a shot over the wall in left field that would have given the Huskies a bit more breathing room but it landed just on the wrong side of the foul pole.
WIth a two out double to center by Thomas in the fourth the only Husky hit the rest of the game that left the outcome of the game on the right arm of Alvelo.
Other than the seventh, the only other inning that the Utes went down in order came in the third. Otherwise they kept the heat on. In the first Barrera singled with one out but got erased when Flippen grounded into a double play.
In the second the first two Utah batters reached base but Alvelo slammed the door by striking out the side. She got the dangerous Kelly Martinez, who owned two home runs in the first two games, swinging.
She then fanned Heather Bowen swinging on a 2-2 pitch, and after nine pitches, got Kay Kay Fronda swinging.
In the fourth Utah had the bases loaded with two outs but Alvelo escaped by retiring Fronda on a groundout to second.
In the fifth Utah put the pressure on Alvelo again. Delilah Pacheco led off with a line single to left center. Castaneda then hit a grounder up the middle that looked like another hit but Sis Bates made a diving stab and flipped the ball to Aguilar for a big fielder's choice putout at second.
Barrera roped a double into left center to put runners on second and third.
That brought up Flippen. After pitching coach Mike Roberts came out to the pitcher's circle for a confab the Huskies took the bat out of her hands, walking her intentionally to load the bases. Anissa Urtez then hit a sinking line drive to right but Melhart raced in to make a terrific diving catch. Castaneda scored on what would go into the books as a sacrifice fly to make it 2-1.
The Utes still had runners at first and second but Bridget Castro grounded out to second to end the threat.
In the sixth the Utes threatened one more time. They had runners at first and second with only one out courtesy of a hit batter and a single by Fronda. WIth the count 0-2 on Pacheco pinch runner Ryley Ball for some reason attempted to steal third but catcher Morganne Flores threw a strike to Taylor Van Zee to nail Ball for a big second out. Pacheco then ended the inning with a flare to Van Zee.
After the dramatic win the Huskies will depart for Oklahoma City on Monday, May 29 and open bracket play against Pac-12 rival Oregon on . the other teams in the Huskies' bracket include defending champion Oklahoma and Baylor, both from the Big 12.